Stranded Subsea Power Cable Buoyancy and Heat Dissipation
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Solution Overview
Problem
Existing subsea power cables face challenges in dissipating heat generated by conductor elements while providing buoyancy, leading to insulation degradation and reduced lifetime expectancy, and are difficult to manufacture, install, and handle due to local stress and size variations from independent buoyancy elements.
Innovation Solution
A subsea power cable design where buoyancy elements are stranded together with conductor elements, allowing for heat dissipation and reducing local stress, featuring a continuous buoyancy element with a density less than water, combined with a strain element made of synthetic yarn for improved flexibility and strength, and an outer sheath for mechanical protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a sheath of high buoyancy material is extruded to reduce cable weight, then cable buoyancy is improved, but heat dissipation capability deteriorates due to encapsulation of the cable
Solution Approach 1:
The cable is divided into multiple independent segments, each with its own buoyancy elements integrated at specific intervals rather than a continuous sheath. This segmentation allows heat to dissipate from the conductor while buoyancy elements provide lift where needed, resolving the conflict between weight reduction and heat dissipation.
Solution Approach 2:
Buoyancy elements are placed locally at specific intervals along the cable rather than providing uniform coverage. This localized approach provides buoyancy where required while leaving other sections open for heat dissipation, allowing the cable to achieve adequate buoyancy without encapsulating the entire conductor.
2Weight of moving object
If independent buoyancy elements are used to reduce cable weight, then cable buoyancy is improved, but cable flexibility and ease of handling deteriorate due to local stress and size variations
Solution Approach 1:
Buoyancy elements are integrated and combined with the cable structure itself rather than being separate attachments. The buoyancy material forms part of the cable's cross-section at intervals, creating a unified structure that maintains flexibility while providing buoyancy, eliminating the handling difficulties associated with separate independent elements.
Solution Approach 2:
Instead of adding separate buoyancy elements to an existing cable structure, the invention inverts the approach by incorporating buoyancy material directly into the cable's construction at intervals. This integration creates a more uniform structure that is easier to handle while still providing the necessary buoyancy.
3Weight of moving object
If independent buoyancy elements are used to provide buoyancy, then cable weight is reduced, but manufacturing complexity increases due to the need to interconnect multiple elements
Solution Approach 1:
The cable construction is segmented into sections with buoyancy material at intervals, allowing each section to be manufactured independently and then assembled. This segmentation simplifies the manufacturing process compared to creating a continuous buoyant sheath, while the regular spacing of buoyancy elements creates a predictable, manageable structure.
Solution Approach 2:
The invention changes the parameter of buoyancy distribution from continuous to discrete intervals. This parameter change simplifies manufacturing by allowing standard sections to be produced and assembled, reducing the complexity of interconnecting multiple elements while maintaining effective buoyancy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The stranded design enables efficient heat transfer, reduces local stress, and improves bending properties, making the cable easier to handle and install, while maintaining buoyancy and extending fatigue lifetime, suitable for dynamic loads and high-temperature applications.
Implementation Method 1
at least one continuous buoyancy element having a density lower than water
Implementation Method 2
the heat from the conductor element(s) is allowed to dissipate
Implementation Method 3
heat transfer from the conductor element(s) to the surroundings of the cable
Data Source
Figure 1
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AI summary
Light weight dynamic subsea power cable comprising at least one conductor element (101), and at least one buoyancy element (2, 3) having a density lower than water, wherein the at least one conductor element (101) and the at least one buoyancy element (2, 3) are stranded together and a method for producing said cable is disclosed.